Struct CheckMetadataHash

pub struct CheckMetadataHash<T> { /* private fields */ }

Extension for optionally verifying the metadata hash.

The metadata hash is cryptographical representation of the runtime metadata. This metadata hash is build as described in RFC78. This metadata hash should give users the confidence that what they build with an online wallet is the same they are signing with their offline wallet and then applying on chain. To ensure that the online wallet is not tricking the offline wallet into decoding and showing an incorrect extrinsic, the offline wallet will include the metadata hash into the extension implicit and the runtime will then do the same. If the metadata hash doesn’t match, the signature verification will fail and thus, the transaction will be rejected. The RFC contains more details on how it works.

The extension adds one byte (the mode) to the size of the extrinsic. This one byte is controlling if the metadata hash should be added to the implicit or not. Mode 0 means that the metadata hash is not added and thus, None is added to the implicit. Mode 1 means that the metadata hash is added and thus, Some(metadata_hash) is added to the implicit. Further values of mode are reserved for future changes.

The metadata hash is read from the environment variable RUNTIME_METADATA_HASH. This environment variable is for example set by the substrate-wasm-builder when the feature for generating the metadata hash is enabled. If the environment variable is not set and mode = 1 is passed, the transaction is rejected with UnknownTransaction::CannotLookup.

Implementations

impl<T> CheckMetadataHash<T>

pub fn new(enable: bool) -> Self

Creates new TransactionExtension to check metadata hash.

pub fn new_with_custom_hash(metadata_hash: [u8; 32]) -> Self

Create an instance that uses the given metadata_hash.

This is useful for testing the extension.

Trait Implementations

impl<T: Clone> Clone for CheckMetadataHash<T>

fn clone(&self) -> CheckMetadataHash<T>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T> Debug for CheckMetadataHash<T>

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Decode for CheckMetadataHash<T>

where PhantomData<T>: Decode,

fn decode<__CodecInputEdqy: Input>( __codec_input_edqy: &mut __CodecInputEdqy, ) -> Result<Self, Error>

Attempt to deserialise the value from input.

fn decode_into<I>( input: &mut I, dst: &mut MaybeUninit<Self>, ) -> Result<DecodeFinished, Error>

where I: Input,

Attempt to deserialize the value from input into a pre-allocated piece of memory.

fn skip<I>(input: &mut I) -> Result<(), Error>

where I: Input,

Attempt to skip the encoded value from input.

fn encoded_fixed_size() -> Option<usize>

Returns the fixed encoded size of the type.

impl<T> Encode for CheckMetadataHash<T>

where PhantomData<T>: Encode,

fn size_hint(&self) -> usize

If possible give a hint of expected size of the encoding.

fn encode_to<__CodecOutputEdqy: Output + ?Sized>( &self, __codec_dest_edqy: &mut __CodecOutputEdqy, )

Convert self to a slice and append it to the destination.

fn encode(&self) -> Vec<u8>

Convert self to an owned vector.

fn using_encoded<R, F>(&self, f: F) -> R

where F: FnOnce(&[u8]) -> R,

Convert self to a slice and then invoke the given closure with it.

fn encoded_size(&self) -> usize

Calculates the encoded size.

impl<T: PartialEq> PartialEq for CheckMetadataHash<T>

fn eq(&self, other: &CheckMetadataHash<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: Config + Send + Sync> TransactionExtension<<T as Config>::RuntimeCall> for CheckMetadataHash<T>

const IDENTIFIER: &'static str = "CheckMetadataHash"

Unique identifier of this signed extension.

type Implicit = Option<[u8; 32]>

Any additional data which was known at the time of transaction construction and can be useful in authenticating the transaction. This is determined dynamically in part from the on-chain environment using the implicit function and not directly contained in the transaction itself and therefore is considered “implicit”.

type Val = ()

The type that encodes information that can be passed from validate to prepare.

type Pre = ()

The type that encodes information that can be passed from prepare to post_dispatch.

fn implicit(&self) -> Result<Self::Implicit, TransactionValidityError>

Determine any additional data which was known at the time of transaction construction and can be useful in authenticating the transaction. The expected usage of this is to include in any data which is signed and verified as part of transaction validation. Also perform any pre-signature-verification checks and return an error if needed.

fn weight(&self, _: &T::RuntimeCall) -> Weight

The weight consumed by executing this extension instance fully during transaction dispatch.

fn validate( &self, origin: DispatchOriginOf<T::RuntimeCall>, _call: &T::RuntimeCall, _info: &DispatchInfoOf<T::RuntimeCall>, _len: usize, _self_implicit: Self::Implicit, _inherited_implication: &impl Encode, _source: TransactionSource, ) -> ValidateResult<Self::Val, T::RuntimeCall>

Validate a transaction for the transaction queue.

fn prepare( self, _val: Self::Val, _origin: &DispatchOriginOf<T::RuntimeCall>, _call: &T::RuntimeCall, _info: &DispatchInfoOf<T::RuntimeCall>, _len: usize, ) -> Result<Self::Pre, TransactionValidityError>

Do any pre-flight stuff for a transaction after validation.

fn metadata() -> Vec<TransactionExtensionMetadata>

Returns the metadata for this extension.

fn post_dispatch_details( _pre: Self::Pre, _info: &<Call as Dispatchable>::Info, _post_info: &<Call as Dispatchable>::PostInfo, _len: usize, _result: &Result<(), DispatchError>, ) -> Result<Weight, TransactionValidityError>

Do any post-flight stuff for an extrinsic.

fn post_dispatch( pre: Self::Pre, info: &<Call as Dispatchable>::Info, post_info: &mut <Call as Dispatchable>::PostInfo, len: usize, result: &Result<(), DispatchError>, ) -> Result<(), TransactionValidityError>

A wrapper for post_dispatch_details that refunds the unspent weight consumed by this extension into the post dispatch information.

fn bare_validate( _call: &Call, _info: &<Call as Dispatchable>::Info, _len: usize, ) -> Result<ValidTransaction, TransactionValidityError>

Validation logic for bare extrinsics.

fn bare_validate_and_prepare( _call: &Call, _info: &<Call as Dispatchable>::Info, _len: usize, ) -> Result<(), TransactionValidityError>

All pre-flight logic run before dispatching bare extrinsics.

fn bare_post_dispatch( _info: &<Call as Dispatchable>::Info, _post_info: &mut <Call as Dispatchable>::PostInfo, _len: usize, _result: &Result<(), DispatchError>, ) -> Result<(), TransactionValidityError>

Post dispatch logic run after dispatching bare extrinsics.

impl<T> TypeInfo for CheckMetadataHash<T>

where PhantomData<T>: TypeInfo + 'static, T: 'static,

type Identity = CheckMetadataHash<T>

The type identifying for which type info is provided.

fn type_info() -> Type

Returns the static type identifier for Self.

impl<T> DecodeWithMemTracking for CheckMetadataHash<T>

where PhantomData<T>: DecodeWithMemTracking,

impl<T> EncodeLike for CheckMetadataHash<T>

where PhantomData<T>: Encode,

impl<T: Eq> Eq for CheckMetadataHash<T>

impl<T> StructuralPartialEq for CheckMetadataHash<T>